I've also had some tricky shrinking type issues with recursive generators using
bind. I had a play with your generators, using such-that to reduce the
row/column name length and also preventing some generator shrinking by using
no-shrink, but I didn't have much luck improving the resulting shrinks (though
the shrinks did finish in a timely fashion).
You might have more luck if you generated an m x n matrix size independently of
the matrix itself and feed the size into the matrix generator and the samples
and probes generators. This may allow the matrix size to be shrunk down more
easily, while also shrinking the samples and probes vectors without them having
to be regenerated for ever new matrix shrink (i.e. where the matrix size is
maintained but the gen/int values within it are shrunk).
However, this is all guess work and conjecture, as I don't understand the
shrinking algorithm well enough, and I haven't tried my suggestion. Also,
modifying your generators in this way may make your model less general if you
wish to use it in other ways later.
Cheers
Lucas
> On 12 Nov 2014, at 02:43, Brian Craft <craft.br...@gmail.com> wrote:
>
> Using test.check, I'm finding the shrinking to be very, very slow. Running a
> hundred cases takes a few seconds, unless it hits an error, in which case it
> takes 40-60 minutes to shrink, and the shrinking is not very effective
> (resulting test case is much larger than necessary). Sometimes the shrinking
> is much faster. It behaves a bit like it's occasionally getting into a
> pathological state, or a difficult shrinking scenario.
>
> Are there any docs on generators or the shrinking algorithm that would help
> build tests that shrink more effectively?
>
> The problematic generator builds a randomly-sized matrix of integers, with
> randomly assigned names for the rows and columns. The failure case is when
> either a column or row name is repeated. I expect the slow shrinking has
> something to do with it being rare for the generator to emit the same name
> twice.
>
> ; Generator of randomly sized matrices of random numbers.
> (def gen-matrix
> (gen/bind
> gen/s-pos-int
> (fn [x] (gen/bind
> gen/s-pos-int
> (fn [y] (gen/vector (gen/vector gen/int x) y))))))
>
> ; Generator of matrix with probe and sample ids.
> (def gen-tsv
> (gen/bind
> gen-matrix
> (fn [m]
> (gen/hash-map
> :probes (gen/vector
> (gen/such-that not-empty gen/string-alpha-numeric)
> (count m))
> :samples (gen/vector
> (gen/such-that not-empty gen/string-alpha-numeric)
> (count (first m)))
> :matrix (gen/return m)))))
>
> Shrinking will result in a case like
>
> {:matrix [[1 4 -3] [-4 -3 -5] [-5 2 3] [4 -5 -5] [1 -2 3] [1 4 1]], :samples
> ["0" "0" "0"], :probes ["0" "0" "0" "0" "0" "0"]}
>
> where :samples ["0" "0"] :probes["0"] would do.
>
> The following test will exhibit the behavior, sometimes succeeding, sometimes
> failing quickly, sometimes shrinking for a very long time:
>
> (tc/quick-check 100 (prop/for-all [tsv gen-tsv] (= (count (set (:probes
> tsv))) (count (:probes tsv)))))
>
> --
> You received this message because you are subscribed to the Google
> Groups "Clojure" group.
> To post to this group, send email to clojure@googlegroups.com
> Note that posts from new members are moderated - please be patient with your
> first post.
> To unsubscribe from this group, send email to
> clojure+unsubscr...@googlegroups.com
> For more options, visit this group at
> http://groups.google.com/group/clojure?hl=en
> ---
> You received this message because you are subscribed to the Google Groups
> "Clojure" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to clojure+unsubscr...@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.
--
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to clojure@googlegroups.com
Note that posts from new members are moderated - please be patient with your
first post.
To unsubscribe from this group, send email to
clojure+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
---
You received this message because you are subscribed to the Google Groups
"Clojure" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to clojure+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
